This invention relates to a pumping system useful in dispensing fluids, especially those that are expensive, viscous, high purity, and/or sensitive to molecular shear. The invention also relates to microelectronic components such as silicon chips and wafers, microelectronic substrates, and circuits fabricated by such pumping systems and methods, including the potentially improved quality and yield of such products achievable with the invention as compared to prior art systems.
General aspects of the relevant background of the invention are discussed in prior U.S. Pat. Nos. 5,167,837; 5,772,899; and 5,516,429. Among other things, the invention has numerous applications, but is especially useful in the microelectronics industry. The trend in that industry continues to be to squeeze greater quantities of circuitry onto smaller substrates. Circuit geometries continue to shrink, the use of expensive materials continues, and the corresponding need for decontaminated "cleanroom" environments and equipment for manufacturing, filtering, and processing continues and even increases. Perhaps as importantly, the need for improved yield of final product continues, for economic and other reasons.
The equipment and methods of the aforementioned U.S. Pat. Nos. 5,167,837; 5,772,899; and 5,516,429 addresses many situations and applications very well. The present invention is directed to further improvements in that technology, as well as potential applications of such improvements in unrelated technologies.
Among other things, further simplification and upright orientation of the flow path for the processed fluids through a pumping and dispensing system can reduce the risk of contamination, air entrapment, or similar concerns, while providing similar or improved reliability and precise control for desired filtration, dispense, and other handling of the process fluids. Further manufacturing and design improvements in the instant invention allow the entire process fluid flow path to be coated or machined from Teflon.RTM. or some similar non-contaminating material, further reducing the likelihood of any contamination problems.
As indicated above, many problems were addressed and solved by the aforementioned U.S. Pat. Nos. 5,167,837, 5,516,429, and 5,772,899. Among other things, those devices introduced a diaphragm-type fluid dispense system which, in certain embodiments, included two separate computer-controlled pumps to dispense precise amounts of fluid. However, the preferred embodiments in those patents show the process fluid traveling in a somewhat meandering path through the pump system. In certain applications, that path does not afford optimal venting for any contaminating air bubbles that may become entrapped in the fluid or the system. For example, some small amount of air bubbles may be unavoidably introduced when the source fluid container is periodically changed, even if no re-priming is required. Portions of the flow path that are metal or otherwise relatively potentially contaminating result in some risk (however small) of corresponding undesirable contamination of the fluid.
As indicated in those prior patents, such bubbles or contaminants could potentially compromise the end product to some degree in some small percentage of applications. Alternatively, such bubbles or contaminants might require some period of "flushing" bubbles from the system upon changing the source fluid container, for example, or might otherwise compromise the accuracy of the fluid dispense system (again, in a small percentage of applications and situations). Although those prior patents and inventions function well in that regard and are a dramatic advance over the prior art before them, and although those prior patents can be readily adapted to deal with the aforementioned potential problems, the instant invention provides improvements in that regard.
Other benefits derive from simplifying the flow path of the fluid. By simplifying and reducing the number of components involved in the system, assembly and maintenance can be correspondingly simplified. Perhaps more importantly, the number of connection points, seals, fittings, and related potential leak-spots can be reduced, thereby directly reducing the risk of contamination, air-entrainment, or similar problems. Additionally, reducing and realigning the fluid flow path can reduce the size of the "footprint" for the housing of the system and otherwise make the system more compact as compared to prior art systems, thereby correspondingly reducing valuable factory space for the users of the pump system.